Macroporous omniphilic sponges

Abstract

The present invention discloses a versatile, macroporous, omniphilic polymeric sponges for absorption of organic liquids of varying polarity as well as water. Particularly, disclosed herein is an ice-templated macroporous omniphilic polymeric sponge as inexpensive versatile absorbents.

We claim: 
     
       1. A macroporous omniphilic compressible sponge, wherein said omniphilic compressible sponge is a reaction product of:
 i. a polymer with at least one free amino or hydroxyl group or both; 
 ii. a cross-linker; and 
 iii. a modifying agent selected from aliphatic or aromatic epoxides, acid chlorides, or aldehydes that tunes the solvophilicity of the sponges; 
 wherein the polymer is selected from the group consisting of polyethyleneimine, poly-ε-lysine, and polyvinyl alcohol, 
 wherein the polymer and cross linker are in the weight ratio ranging from 1.2:1 to 1.5:1; and 
 wherein the total volume of macropores is between 60-95% of the geometric volume of said macroporous omniphilic compressible sponge, said sponge absorbs each of hexane and water individually more than 4 times the weight of the macroporous omniphilic sponge, and said sponge recovers completely after compression to strain of greater than 0% up to and including 80%. 
 
     
     
       2. The omniphilic compressible sponge according to  claim 1 , wherein the cross-linker is selected from the group consisting of epichlorohydrin, 1,4-butanediol diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, PEG diepoxide, polypropylene glycol diglycidyl ether, glycerol polyglycidyl ether, sorbitol polyglycidyl ether, aldehyde; 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), N,N′-dicyclohexyl carbodiimide (DCC), N,N′-diisopropylcarbodiitnide (DIC); and isocyanate. 
     
     
       3. The omniphilic compressible sponge according to  claim 1 , wherein the modifying agent is selected from the group consisting of aromatic and C4 to C17 aliphatic epoxides, acid chlorides, and aldehydes. 
     
     
       4. The omniphilic compressible sponge according to  claim 1 , wherein the weight ratio of modifying agent: polymer+cross linker is in the range of 1:0.3 to 1.5:1. 
     
     
       5. The omniphilic compressible sponge according to  claim 1 , wherein said omniphilic compressible sponge is stable to compression-expansion at 500 cycles. 
     
     
       6. A process for producing the macroporous, omniphilic compressible polymeric sponge that can absorb each of hexane and water individually more than 4 times the weight of the macroporous, omniphilic compressible polymeric sponge according to  claim 1 , comprising:
 i. providing an ice-templating method comprising refrigerating a mixture of a polymer with free amino or hydroxyl group in water and a cross-linker by maintaining the temperature at 15° to 20° C. for about 24 hours until a mesh is observed, thawing and drying to obtain an ice-templated hydrophilic cross linked polymeric sponge; and 
 ii. covalently coupling the dried polymeric sponge of step (i) with a modifying agent selected from aliphatic or aromatic acid chlorides, aldehydes, or epoxides to tune the solvophilicity of the sponge to obtain the omniphilic compressible sponge. 
 
     
     
       7. The macroporous, omniphilic compressible polymeric sponge according to  claim 1 , wherein the sponge is useful to control oil spills in water bodies, laboratories, or in an industrial setting by selective absorption of organic fluid and water.